Dimerization of c2 to c10 olefins with deposited catalyst

ABSTRACT

IN THE DIMERIZATION OF C2 TO C10 OLEFINS IN A LOOP REACTOR, THE IMPROVEMENT COMPRISING RUNNING THE REACTOR HOTTER THAN NORMAL FOR A SHORT PERIOD OF TIME UNTIL CATALYST AND POLYMER ARE DEPOSITED ON THE WALLS OF THE LOOP REACTOR MAKING THE REACTOR MORE SELECTIVE FOR DIMERIZATION, AND THEN RETURNING TO THE USUAL REACTION TEMPERATURES. AS A SECOND FEATURE, BY RUNNING THE EFFLUENT FROM THE LOOP REACTOR THROUGH A FIXED BED OF ION EXCHANGE RESIN, SOME OF THE CATALYST FROM THE STREAM DEPOSITS ON THE ION EXCHANGE RESIN, AND THERE ACTS AS A SECOND CATALYST BED SELECTIVE FOR DIMERIZATION.

Dec. 28, 1971 T. HUTsoN, JR., ETAL A 7' TORNEI/5 United States Patent O 3,631,121 DIMERIZATION F C2 T0 C10 OLEFINS WITH DEPOSITED CATALYST Thomas Hutsou, Jr., and Cecil 0. Carter, Bartlesville, Okla., assignors to Phillips Petroleum Company Filed May 12, 1969, Ser. No. 823,618 Int. Cl. C07c 3/10 U.S. Cl. 260-683.15 D 9 Claims ABSTRACT 0F THE DISCLOSURE In t-he `dimerization of C2 to C10 olefins in a loop reactor, the improvement comprising running the reactor hotter than normal for a short period of time until catalyst and polymer are deposited on the walls of the loop reactor making the reactor more selective for dimerization, and then returning to the usual reaction temperatures. As a second feature, by running the effluent from the loop reactor through a fixed bed of ion exchange resin, some of the catalyst from the stream deposits on the ion exchange resin, and there acts as a second catalyst bed selective for dimerization.

FIELD OF THE INVENTION This invention relates to dimerization of olefins in a loop reactor and/or fixed bed reactor. Possibly class 260 'Chemistry, Carbon Compounds subclass 683115 Acyclic, olefines from hydrocarbons, by polymerization of ole-fines, catalytic is the most pertinent subclass, containing Coopersmith et al. 2,9 118,508, Walker et al. 3,134,824 and Cannell et al. 3,355,510 (all discussed below). Class 23, Chemistry, subclasses 28-8 Apparatus, catalytic and 289I High pressure may contain similar apparatus.

DESCRIPTION OF THE PRIOR ART A preliminary search cited the following U.S. patents:

2,918,508, Dec. 22, 1959, Coopersmith et al., teaches polyisobutylene production in a loop reactor 18-21, followed by a filter 31, and using BF2 as catalyst. This patent is producing heavy polymer, and not dimer, no deposit in the loop reactor occurs and no further reaction in the filter occurs.

3,123,571, Mar. 3, 1964, Walker et al., hydrogenates olefins with a catalyst impregnated silica support. It is not otherwise pertinent.

3,134,824, May 26, 1964, fWalker et al., polymerizes ethylene with biscyclopentadienyl nickel supported on silica, alumina, titania, zirconia, thoria, or boria. While about 60% dimers were produced, about 40% was heavier polymers.

3,157,712, Nov. 17, 19'64, Walker et al., polymerizes 1- olefins with diarene metal compounds deposited on solid supports. It is not particularly pertinent.

3,155,627, Nov. 3, 19164, Cole et al., deposits metallic catalyst on the wall of a reactor with ammonia and hydrogen. It is not particularly pertinent.

3,163,682, Dec. 29, 1964, Walker et al., hydrogenates oleiins with biscyclopentadienyl chromium and nickel compounds on solid supports. It is not otherwise pertinent.

3,248,179, Apr. 26, 1966, Norwood, shows a loop reactor. It is used for ma-king solid polymers, and does not teach dimerization in a loop reactor. Column 7, line 30, states the loop is substantially free from polymer deposits when operated at recommended speed of circulation.

3,305,600, Feb. 2l, 1967, Hopper et al., teaches producing long-chain aluminum alkyls in a single pass system. It is not considered pertinent.

3,353,923, Nov. 21, 1967, Peters, teaches depositing a coating of catalyst components on the inner wall of reac- 3,631,121 Patented Dec. 28, 1971 tor pipes. A chelate polymer which is an organic cyanic compound is preferred. The reactor is used for vapor phase catalytic oxidation of aromatic hydrocarbons. It is otherwise not pertinent.

3,355,510, Nov. 28, 1967, Cannell et al., teaches the same catalyst for dimerization of olefins but no deposit occurs because it is not in a loop reactor.

SUMMARY OF THE INVENTION In the dimerization of C2 to C10 olefins in a loop reactor, the improvement comprising running the reactor hotter than normal for a short period of time until catalyst and polymer are deposited on the walls of the loop reactor making the reactor more selective for dimerization, and then returning to the usual reaction temperatures. As a second feature, by running the effluent from the loop reactor through a xed bed of ion exchange resin, some of the catalyst from the stream deposits on the ion exchange resin, and there acts as a second catalyst bed selective for dimerization.

BRIEF DESCRIPTION OiF THE DRAWING The single figure of the drawing is an elevational view of preferred apparatus comprising a loop reactor and a .fixed bed trim reactor receiving the effluent from the loop reactor, used in the selective dimerization of C2 to C10 olefins, particularly for the dimerization of ethylene.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing, in order to start up, it is preferred to fill the ethylene or other selected olefin solution vessel 1 with a hydrocarbon liquid, such as normal hexane, or any one of, or any mixture of light parafiinic, olefinic, or aromatic hydrocarbons which are liquid at about 300 p.s.i.g. at about 70 F. The filling is from line 2 through valve 3, until liquid level control 4 indicates a liquid level at a predetermined elevation in vessel 1 by actuating the motor 6 opening valve 7. Then valve 3 is closed, and the system is ready to start.

Gaseous dry ethylene or other selected olefin feed from line 8 enters the system through valve 9 whenever the pressure in vessel 1 falls below about 300 p.s.i.g. at pressure recording controller 11 which then operates motor 12 to open valve 9. A check valve 13 in line 8 prevents recycle ethylene or other selected olefins in line 14 from going through valve 13 into the dry ethylene or other selected olefin source. The selected olefin may be any C2 to C10 olefin, or any mixture of them, as all are operative in the process of the present application.

Vessel I1, pipes 16, 17, 18, 19 and 21, heat exchanger 22, and pump 23 are connected in a closed loop forming what is known as a loop reactor, generally designated as 24. Loop reactors are old; see parts 18, 19, 20 and 21 of Coopersmith et al. 2,918,508, Dec. 22, 1959.

In order to initiate the dimerization reaction, suitable amounts of one, two, or more suitable catalysts are injected into pipe 16, for example ethyl aluminum dichloride catalyst through line 26 and valve 27 and tri-n-butyl phosphine nickel dichloride catalyst through line 28 and valve 29. Ethylene, or whatever olefin is to be dimerized, such as a C2 to C10 olefin, is added to loop reactor 24 through line 8 and valve 9. The inside surface of loop reactor 24 is then coated with a third catalyst comprising said first two catalysts mixed with a heavy polymer formed by operating the loop reactor 24 at temperatures of 135 to 200 F. for 60 to 10 hours, and preferably from 135 to F. for 60y to 210 hours, respectively, the hotter the temperature the shorter the time of operation necessary to deposit the third catalyst on the walls of the loop reactor 24.

The catalysts preferably employed may be any of those covered by the claims of Cannell et al. 3,355,510 of Nov. 28, 1967, namely any hydrocarbon soluble nickel compound mixcd with any alkyl aluminum halide. The solid polymer deposited with the catalyst on the walls of the loop reactor 24 obviously is a polymer of the olefin being treated at the high temperature of 135 to 200 F. At the normal dimerization temperature of 40 to 130 F., preferably 65 to 125 F., very small and negligible amounts of this solid polymer will be formed with thc catalyst preferably employed present, as they are, then selective to dimerization instead of solid polymerization of the olefin present at that temperature. The deposit on the walls of the loop reactor 24 produced by the process of the present invention makes the system even more selective to dimerization when operated between 40 and 130 F. than the system would be without said deposit produced only by the solid polymer depositing period of to 60 hours at elevated temperatures of 135 F. to 200 F. The time needed for deposit of solid polymer and also the time for dimerization increases from the C2 to the C10 hydrocarbons, so operations with the C2 to C4 hydrocarbons are preferred.

yOther known dimerization catalysts are employed successfully in the process of the present invention, land are deposited in a layer of solid olefin polymer on the walls of the loop reactor at the named elevated temperatures, and the deposit acts as an increased dimerization selectivity catalyst at the above named normal dimerization temperatures, the same as the preferred catalysts of the preceding paragraph.

As the liquid level rises in vessel 1, control 4 opens valve 7 in product withdrawal line 31 from loop reactor 214, and the product is pumped by pump 32 through trim reactor generally designated as 33. Reactor 33 is cooled by indirect heat exchange with cooling water in cooling coil 34. The product from 32 passes through a fixed bed in reactor 33, the bed preferably being any known ion exchange resin of the prior art. As such resin, Amberlyst made by Rohm & Haas Company is preferred. However, any non-aqueous type ion exchange resin may be used successfully in the present invention.

Amberlyst 15 is a macro-reticular ion exchange resin often used as a catalyst.

Ion exchange resins are insoluble crosslinked polymers of various types in bead form. They are available in various grades ranging from strong acids to strong bases and of varying exchange capacity and porosity. They remove cations or anions from aqueous and non-aqueous solutions, are reversible, and can be regenerated and used again.

While better results are obtained with ion exchange resin in the trim reactor, such as Amberlyst 15, or any Amberlite made by Rohm & Haas Company, useful results in the practice of this invention can be obtained with any solid packing material in the trim reactor, such as sand, diatomaceous earth, bauxite, attapulgus clay, ion exchange resins, molecular sieves, stainless steel wool, broken glass, or glass wool.

While some of the catalyst is collected on packing 36, some passes out overhead line 37 through flow meter 38 into product fiash tank 39 where the C2 to C4 hydrocarbons vaporize and pass out overhead line 4,1, while the heavier hydrocarbons, polymers, and soluble catalyst pass out the lower line 42 whenever liquid level control 43 finds the liquid level in tank `39 exceeds a set point and opens motor valve 44 in response thereto.

Liquid passing valve 44 into line 46 enters a first catalyst removal scrubber 47, preferably filled with packing, where it is washed with a dilute acid solution 48. Any dilute acid may be employed, preferably hydrochloric, nitric or sulfuric acid. A 1 percent solution in water is preferred, and hydrochloric acid is preferred.

The hydrocarbon phase passes out the overhead line 49 4 of the acid scrubber into a caustic scrubber 51. The aqueous phase passes out the bottom line 52 to pump 53 which recycled some to scrubber 47 through recycle line 54 and discharges the remainder through line 56 to a sewer.

"the liquid in line 49 is scrubbed in scrubber 51 with a dilute caustic solution 57. Any dilute caustic can be used, such as alkali metal, alkaline earth metal, or ammonium hydroxides, or amides. A 1 percent solution in Water is preferred, and sodium hydroxide is preferred.

The catalyst-free overhead hydrocarbon phase is passed through line 58 to one of driers 59 or 61, the other drier being regenerated in the conventional manner. As the particular drier employed is not critical to the invention, no further description is believed necessary. Driers 59 and 61 can contain fixed beds of bauxite, or other regeneratable desiccant material.

The aqueous phase 62 emerges from the bottom of scrubber 51 and part is recycled by pump 63 through line 64, and part sent to the sewer through line 66.

Hydrocarbons from driers 59 and 61 pass through line 67 into ethylene stripper column 68 while C2 to C4 hydrocarbons enter column 68 from line 41. Ethylene passes overhead from column 68 through line 69, any excess can be drawn off through line 71 through valve 72, the remainder recycled to the loop reactor 24 through line 14, and any ethylene needed can be added from valve `13 and line 8.

Column 68 can be provided with a refiux condenser 73 and/or a reboiler 74 of conventional construction. The deethanized hydrocarbons pass out bottom line 76 into product fractionator 77 which may also have conventional reflux condenser 78 and reboiler 79, and has an overhead product line 81 for C3 and C4 hydrocarbons, an intermediate product line 82 for C5, C6 and C7 hydrocarbons, and a kettle product line 83 for C8 and heavier hydrocarbons. Obviously, if desired, these hydrocarbons may be split into different groups, or the fractionation can be made into many product lines (not shown) with C4, C5, C6, C7, C8, C9 and C10 and heavier, each coming out a separate product line.

As the specific fractionation system employed at 68 and 77 is not critical to the invention, no further description is necessary as it is just conventional fractionation into whatever products present are desired, except that in line 69 only ethylene is recycled.

While not essential to the operation of the invention, various controls are described solely because it is applicants duty to teach the best way to practice his invention. Obviously, as loop reactor 24 produces dimer, it is necessary to drain liquid through valve 7 controlled by liquid level control 4. As this liquid increases in tank 39, it is necessary to drain it off to fractionation through valve 44 controlled by liquid level control 43. While not essential, it is preferred to keep pump 32 loaded regardless of whether valve 7 is open or closed, and this is done by measuring fiow at 38 and keeping it constant by means of flow rate controller opening or closing valve 86. While not essential, it is preferred to have a constant recycle of liquid from line 42 to loop reactor 24 through line 87 measured by fiow meter 88 and controlled by flow rate controller 89 and valve 91.

EXAMPLE The system was run with loop reactor 24 at an average temperature of about F. for 24 hours, which formed a catalyst coating about 3 mils thick on the interior walls of said loop reactor. Chemical analysis showed the coating to be about 40 percent highly cross linked polymer substantially insoluble in hydrocarbons, the remainder being catalyst and residue. The same feed rates were used in the 24 hours at 160 F. and in the ensuing normal temperature run at 79.5 F.

The feed rates were:

TABLE II.-ETHYLENE DIMERIZATION AT NORMAL TEMPE RAT URE Coated Not coated Process conditions:

Length of run, hours 11 11 Temperature of reactor, F. 79.5 80 Pressure in reactor, p.s.i.g 299 300 Residence time iu reactor, min 46. 3 46. 3 Catalyst molecular ratio: Al/Ni 15.4 15. 4 Conversion and yields:

Ethylene conversion, percent 73.0 73. Butene selectivity, percent. 85.4 76.9 Hexene selectivity, percen 12. 9 20.0 0g+selectivity, percent.-. 1. 7 3. 1 04:yield, percent 62. 3 56. 1 0:ye1d, percent 9. 4 14. 6 +yield, pei cent A 1. 3 2. 3 Total product, lbs/lb. N1 Comp 124, 700

Product analysis in line 31:

02:, Weight percent 26. 5 26. 5 04:, weight percent 61. 1 55.1 m05, weight percent 1. 9 1. 9 08:, weight percent 9. 2 14. 3 08+, weight percent 1. 3 2. 2

Total, Weight percent 100. 0 100. 0

Product analysis in line 37:

0u-, weight pel cent. 9. 3 9. 3 04:, Weight percent 70. 9 64. 9 n05, weight percent 1. 9 1. 9 05:, Weight percen 15. 1 20. 2 03+, weight percent 2. 8 3. 7

Total 100. 0 100. 0

Conversion and yields in line 37:

Ethylene conversion, percent 90. 5 90. 5 Butone selectivity, percent. 79. 8 73.1 Hexene selectivity, percent 17. 0 22. 7 Cg+selectivity, percent 3. 2 4. 2 C4:yield, percent- 72. 2 65. 2 0:yield, percent. 15.4 20.5 P 0s+yiel1d percent.-. 2. 9 3. 8

roduct yie s:

Butenes in line 81, lbs/hr 5. 33 4.88 Hexenes in line 82, lbs./hr- 1. 14 1. 52 03+ in line 83, lbs/hr 0. 21 0. 28

The data in the second column of Table II headed Coated is actual data recorded during an actual run. The data in the third column headed Not Coated is calculated from actual data obtained in a run at 147 p.s.i.g. taking into account the expected values that would be obtained if the pressure was 300 p.s.i.g. instead of 147 .s.1. p Thee trim reactor increases over-al1 ethylene conversion from 73.0% to 90.5%. This results in a 17.5% reduction in the volume of ethylene recycle to the loop reactor.

While a certain preferred system has been described for illustrative purposes, the invention is not limited thereto.

Having described our invention, we claim:

1. In the process of dimerizing at least one C2 to C10 5 olefin in a reactor in the presence of a catalyst selective to dimerization, wherein said catalyst comprises hydrocarbon soluble nickel compound mixed with aluminum alkyl halide, the improvement comprising operating the reactor at 13'5 to 200 F. for 60 to 10 hours to form Ia catalyst film deposit on the interior Walls of the reactor, and then dimerizing the olefin with a reactor temperature between 40 and 130 F. to selectively dimerize the olen and avoid forming heavy polymers.

2. The process of claim 1 in which the reactor temperature for dimerization is between and 125 F.

3. The proces of claim 1 in which the olefin being dimerized is ethylene.

4. The process of claim l in which the eluent from the reactor passes through a trim reactor containing a bed of solid packing material, which collects catalyst deposit and becomes Selective to further dimerization of oleiins.

5. The process of claim 4 in which the reactor temperature for dimerization is between 65 and 125 F.

6. The process of claim 4 in which the olefin being dimerized is ethylene.

7. The process of claim 4 in which the solid packing material is selected from the group consisting of sand, diatomaceous earth, bauxite, attapulgus clay, ion exchange resin, molecular sieve, stainless steel Wool, broken glass, and glass wool.

8. The process of claim 1 in which the olen being dimerized is a `C2 to C4 olefin, and the reactor is mn at to 160 F. for 60 to 20 hours to form the catalyst tilm deposit.

References Cited UNITED STATES PATENTS Wilke m30-683.15 X Drew 260-683.15 X Zuech 260-683.15 X Taylor et al 260-683.l5 Faltings et al. 260-683.15

PAUL M. COUGHLAN, IR., Primary Examiner U.S. Cl. X.R.

252-429 B; 260-94.9 CB 

